Baffles in an Unvented Attic
rhl_ | Posted in General Questions on
Does an unvented attic (namely no soffit or ridge vents to speak of), require baffles when insulating the floor? how about the ceiling?
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You need no baffling baffles if you have an unvented attic.
The purpose of baffles is twofold: the main function is to ensure a pathway for airflow from soffit vents to the ridge (or at least to the open space of the attic) that is unobstructed by insulation out at the eaves. The second function is to prevent windwashing of the insulation out at the eaves around the area of the exterior wall top plates. With no soffit vents, baffles are of limited usefulness, and in an unvented attic, baffles really serve no purpose at all.
Now if you had an insulated attic with insulation up in the rafters instead of on the floor, then your baffles would go between the insulation and the sheathing. The purpose of the baffles is to ensure a pathway for ventilation air in this case from the eave to the ridge, but you still need soffit (intake) vents, and a ridge (outlet) vent for this to work.
If you have any plans to ever convert to a vented attic, and you're doing insulating or air sealing work now, you may want to consider installing baffles now since it's much more difficult to add them as a retrofit later.
I hope this helps you to be less baffled by your baffles :-)
(love that question title, BTW :-)
In addition to what Bill shared, Martin Holladay can shed some light on your baffle confusion (not that you need baffles for your unvented attic, but in case you want to understand where they make sense): Site-Built Ventilation Baffles for Roofs.